HAZARDS OF ANTI HYPERTENSIVE WITHDRAWAL BEFORE SURGERY

Surgical patients on chronic antihypertensive therapy present a management problem in the peri-operative period. 'There seems to be a growing consensus, however, that continuation of the therapy, and control of tHe patient's blood pre'ssure, provide tlie most optimal i:ondliions for aneSthesia In this high·risk group. ' The. following case supports this. A 75-year-old man was admitted for staged bilateral total hip replacement. Hypertension had been controlled for 2 years with reserpine (0.1 mg), hydrallazine (25mg), and hydrochlorothiazide (I 5mg) tid. On admission BP (recumbent) was 190/1 OOmm Hg and pulse 70/min and regular. Antihypertensive medication was discontinued 2 days before the operation. About 1 hour after surgery started BP dropped rapidly to 90/60mm Hg. This responded to mephentermine (7.Smg) IV and infusion of 1 unit of blood. The patient's condition remained stable (BP 140/90-180/11 Omm Hg) during the operation. During recovery BP measured with a BP cuff was 190/1 1 Omm Hg but an arterial line calibration read over 250/1 70mm Hg. There was evidence of left-sided heart failure and pulsus alternans. Morphine ( 4mg) IV was ineffective, but sodium nitroprusside drip reduced BP to 160/110 mm Hg. This was followed by IV hydrallazine for 2 hours. The next morning his preoperative antihypertensive medication was reinstituted and BP satisfactorily controlled. Events were similar during a second hip operation 2 weeks later. 'It is our conviction that the acute withdrawal of antihypertensive medication was a major contributor to the development of the extreme hypertension seen in this patient.'

Katz, J.D. etal. : American Heart Journal92: 79 (Jull976)